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Latest Cumulus MX release v3.0.2 build 3052 - 13 September 2019.
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Temperature 'Feels' variance

Discussion of the Weather34 web site template

Moderators: saratogaWX, weatherist34

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Chapel
Posts: 82
Joined: Mon 30 Jul 2018 10:23 am
Weather Station: Instromet
Operating System: Raspbian
Location: Binbrook UK
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Temperature 'Feels' variance

Post by Chapel » Wed 01 May 2019 10:34 am

I am currently running the 2018 version of Weather34 alongside the latest build and noticed a variance in the temperature 'Feels' field. Now I have to say this particular measurement is not important to me, in fact I am more concerned that my humidity sits at 100% a lot of the time and I will take a closer look at the sensor this coming weekend.

Given that the source data for both screens is the same, can anyone tell me how this temperature is calculated and why the difference between versions?
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PaulMy
Posts: 1934
Joined: Sun 28 Sep 2008 11:54 pm
Weather Station: Davis Vantage Pro 2+ w/Envoy USB
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Location: Komoka, ON Canada
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Re: Temperature 'Feels' variance

Post by PaulMy » Wed 01 May 2019 1:34 pm

I am not a coder but decided to have a look and found a livedata.php script in the template set. In this script it has temp_feel variable which I presume is the 'feels like'. Comparing most recent vs older versions it looks like the calculation has changed between these versions.

The most recent version by SaratogaWX in livedata.php has: $weather["temp_feel"] = apparent_temperature($weather['temp'],$weather['humidity'],$weather['wind_speed']);
The first version posted by SaratogaWX dated January 4, 2019 has: $weather["temp_feel"] = heatIndex($cumulus[2], $cumulus[3]); // must set temp_units first
An August 2018 version from Brian the livedata.php has: $weather["temp_feel"] = heatIndex($cumulus[2], $cumulus[3]); // must set temp_units first

So it appears that in the most recent version Ken has modified Brian's calculation and that gives a slightly different result.

Enjoy,
Paul

EDIT:
I am also testing Wim's (Leuven Template author) Weather Underground version that uses the WU API and that shows a different result as well. The FeelsIike variable in the temperature_block is much different. Therefore, as the script authors have said, it is important to not mix between the versions.
http://www.komokaweather.com/pws-wu/index.php Wim's version for WU API
http://www.komokaweather.com/pws/index.php Ken's version for Cumulus 1 and MX
http://www.komokaweather.com/pws-wfl/in ... theme=dark Ken's version for Cumulus but using the WiFiLogger realtime.txt file (which is the same format as the Cumulus reasltime.txt file but does not have all of the data that is calculated by Cumulus).

Chapel
Posts: 82
Joined: Mon 30 Jul 2018 10:23 am
Weather Station: Instromet
Operating System: Raspbian
Location: Binbrook UK
Contact:

Re: Temperature 'Feels' variance

Post by Chapel » Wed 01 May 2019 3:05 pm

Thank you for that, it actually felt quite warm out with the dogs this afternoon, so I am inclined to agree with the latest version despite my view being quite subjective :)

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